We have a mail server running MCIS 2.0 on NT4.0 that has been working fine. However, in the last couple of days the pop3 stops working along with the local website. You can go to other websites fine. If you stop and restart smtp service everything goes back to working for about five minutes. I have restored by data and operating system back to a known good working session from my tape backup. I have changed out the memory and broke my mirrored drives and used just one of the two drives at a time. Performance monitor shows indicates that everything is fine. I suspect the motherboard is playing out, I don't think the problem lies with the nic card because I can go to other websites fine and that seems to prove my DNS server is okay. I have scanned for viruses and trojans. Any thoughts or suggestions would be apprecitated.